The educational environment has been increasingly acknowledged as vital for high-quality medical education. As a result, several instruments have been developed to measure medical educational environment quality. However, there appears to be no consensus about which concepts should be measured. The absence of a theoretical framework may explain this lack of consensus. Therefore, we aimed to (1) find a comprehensive theoretical framework defining the essential concepts, and (2) test its applicability. An initial review of the medical educational environment literature indicated that such frameworks are lacking. Therefore, we chose an alternative approach to lead us to relevant frameworks from outside the medical educational field; that is, we applied a snowballing technique to find educational environment instruments used to build the contents of the medical ones and investigated their theoretical underpinnings ("Study 1"). We found two frameworks, one of which was described as incomplete and one of which defines three domains as the key elements of human environments ("personal development/goal direction", "relationships", and "system maintenance" and "system change") and has been validated in different contexts. To test its applicability, we investigated whether the items of nine medical educational environment instruments could be mapped unto the framework ("Study 2"). Of 374 items, 94% could: 256 (68%) pertained to a single domain, 94 (25%) to more than one domain. In our context, these domains were found to concern "goal orientation", "relationships" and "organization/regulation". We conclude that this framework is applicable and comprehensive, and recommend using it as theoretical underpinning for medical educational environment measures.